Cancer tahiticus Curtiss, 1938

Ng, Peter K. L., Eldredge, Lucius G. & Evenhuis, Neal L., 2011, The names of decapod and stomatopod Crustacea from Tahiti, French Polynesia, established by Anthony Curtiss in 1938 and 1944, Zootaxa 3099, pp. 43-56 : 48

Cancer tahiticus Curtiss, 1938 [tupa]

Cancer carnifex Herbst, 1796: 163 .

Cancer tahiticus Curtiss, 1938: 170 , n. syn.

There are two species of land crabs in French Polynesia, the large Cardisoma carnifex (Herbst, 1796) , which lives closer to the sea, and the smaller, forest dwelling Discoplax rotunda ( Quoy & Gaimard, 1824) (Gecarcinidae) . The description of Cancer tahiticus agrees best with C. carnifex , with the colour “dull pale bluish-green above, with a reddish-brown tinge, and becoming purplish towards the rear.” The sides and the region under the eyes are lavender. The legs and tail (which is folded up close against the thorax) are whitish, variegated with pale orange and bluish” ( Curtiss 1938: 170) agreeing well with the species. Curtiss nevertheless noted that Cancer tahiticus grew to only “an inch and seven-sixeenths wide … left claw is a little larger than the other, but not much”. This suggests he only observed small specimens since adult specimens of Cardisoma carnifex reach almost 10 cm in carapace width and males have one of the chelae strongly enlarged and much larger than the other. French Polynesia is the extreme eastern limit of its distribution ( Türkay 1974). The form of the chela (“pincers are almost smooth”) and colour, however, suggests it is not Discoplax rotunda , which is a shy species not often seen ( Ng & Guinot 2001).